The first wave of documents released by Wikileaks show the U.S. as a superpower secretly struggling to maintain its hold on an increasingly chaotic world. So far, Canada has been spared.

WASHINGTON—From caustic snapshots of world leaders to deep misgivings about many of its own allies to secret plans to topple governments, the long-awaited WikiLeaks onslaught is proving precisely the diplomatic nightmare Washington feared it would be.

Embarrassment and anger abound in Washington and far beyond as governments everywhere pore over the emerging diplomatic cables, taking measure of the damage.

Canada was spared in the initial wave of secret State Department memos released Sunday — but likely not for long.

More than 2,600 classified U.S. dispatches mentioning Canada — including nearly 100 designated “secret” — are on the verge of exposure, as online whistler-blower WikiLeaks and its five media partners spill basket upon basket of diplomatic dirty laundry in daily installments throughout the week.

Nearly everyone else, however, has already taken a hit, as hand-picked news organizations including the New York Times and The Guardian deliver their takes on the trove of more than three million raw and often unflattering documents showing the world and its troubles through American diplomatic eyes.

Among the early revelations in what is far and away the most significant breach in diplomatic history is a 2009 memo under Secretary of State Hillary Clinton’s name that sanctioned a blurring of the lines between diplomacy and spycraft, directing U.S. officials to gather intelligence on top United Nations executives.

Other documents written as embassy field reports offer unvarnished and occasional scathing assessments of world leaders. One describes Vladimir Putin as Russia’s “alpha-dog.”

But the leaks, unveiled in a single coordinated online splash Sunday afternoon, also brought into high relief America’s struggles to exercise global influence.

Some cables describe U.S. diplomatic setbacks, including failed attempts to block Syria from shipping arms to the militants of Hezbollah, to curb terror funding in Qatar and to contain Chinese attempts to hack U.S. computers.

The leaks also offer unprecedented detail on the Obama administration’s extensive efforts to build international consensus against Iran’s nuclear program. One cable raises the possibility that Iran, with help from North Korea, possesses powerful missiles that bring European capitals in range.

Reaction in Washington was fast and furious. The White House denounced the disclosures as “reckless and dangerous,” and prominent congressional leaders called for arrest of the principals behind WikiLeaks. But U.S. officials declined to discuss the individual leaks in any detail.

Canada chimed in with a statement from Foreign Affairs Minister Lawrence Cannon, who branded the leaks “irresponsible, deplorable” and a potential threat to national security.

Reaction overseas was all over the map. Italian Foreign Minister Franco Frattini called the embassy cables “the Sept. 11 of world diplomacy.”

The British Foreign Office was more muted. But in denouncing cables that are expected to present unflattering U.S. descriptions of key British leaders later this week, the U.K.’s statement stressed, “We have a very strong relationship with the U.S. government. That will continue.”

The diplomatic embarrassment could be especially difficult in certain Islamic countries. Disclosures involving Egypt, Saudi Arabia, Yemen and Pakistan range from contretemps over Iran’s nuclear ambitions to field reports that detail some of the unseen diplomatic arm-twisting that accompanies the U.S. war on terror.

The lone significant Canadian mention in Sunday’s batch of cables describes a September 2009 encounter in Kandahar in which Canadian and U.S. officials grill Ahmed Wali Karzai, half-brother of the Afghan president, who is widely seen as the single most powerful power-broker in the corruption-plagued province.

Canada’s senior diplomat in Canada, Ben Rowswell, is quoted as asking about the credibility of Afghan elections. Karzai is quoted as saying democracy is a new experience for Afghans, most of whom do not understand the point of having one election, let alone two.

“The people do not like change,” Karzai says to his questioners. “They think: The president is alive and everything is fine. Why have an election?”

The New York Times, The Guardian and Le Monde of France all acknowledged using precautionary editorial judgment, withholding especially sensitive documents deemed a risk to individuals or national security.

The German magazine Der Speigel, another of WikiLeaks partners, which dedicated a team of 50 reporters scouring its advance copies of the documents over the course of several weeks, described their overall heft as a portrait of a superpower fraught with doubts.

“Do they really show a U.S. which has the world on a leash?” Der Spiegel wrote in an analytical assessment of its findings.

“In sum, probably not. In the major crisis regions, an image emerges of a superpower that can no longer truly be certain of its allies – like in Pakistan, where the Americans are consumed by fear that the unstable nuclear power could become precisely the place where terrorists obtain dangerous nuclear material.”

Just as its media partners begin to publish online, WikiLeaks’ online website suffered a temporary outage, which the organization attributed to a denial-of-service attack by unknown hackers seeking to prevent the disclosures. But the site resumed service later Sunday afternoon, with fresh postings of hundreds of the secret cables.